Sound intensifier



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Patented Sept.7 29, 1925.

UNITED STATES www nimmer: .1. xoEnLm, or roel-renne,

BOUND INTENSITIER,

Appuiuon ma February 24, 192s. seen :nu une,

reproduees sounds true to t `reir natural tones' yet greatly increased in volume, moreover' lthont the use of any horn.

Other objects and advanta are to be found in the construction an arrangement of parts as will be described in the specification, and particularly pointed out 1n the appended claims. i

I attain-these objects with the mechanism ilhistreted in the accompanying drawing, in which: f

Fig; l is a plan View of the entire mechanism.

2 is a side elevation partly in sention.

@Ver a frame stretched e membrane 2 preferably com posed of the skin of e calf or sncnlike ani-5 mal; to obtain the best results it is important that the skin be stretched as tight as the limits of elasticity will permitJn This skin or Arnen'ibrane Q is glued to a hoop 3, and the edge 4 of said membrane bent upward for greater security against slipping. A slip ring 5 presses against the hoop 5J and holds the membrane L. tight. pins 6 hold the slip ring 5 and frame 1 together. At the center of the membrane 2 and parallel thereto is a vibrating unit composed of a metal cross 7 Whose ends are bent'toward the membrane 2 and terminate fiat pointed prongs 8. Thin sharp pointed prongs would pierce the membrane too quickly, the contact surface of the prongs must therefore be proportioned to the strength of the membrane Q. The metal cross 7 is held to the membrane 2 by means of the screws 9, the Washers l0 being inter`- posed to prevent the cutting of the 'memf Although the screws 9 should be l of suitable material isbeing located es close as powib ter should not `the screws :9, bet sir' amount o. flexible :one respective edges f5.,

firmly secured io cross 7 le t for a suitable dicton o to 'prevent 'intenl tiene of the mf pin il as tb tfansmitteld to 8. Viin"vtionv wood pin il cphone, pli-cnog.. means, and the res be greatly incrcasen from harsh meta- Elie n Having thus al will be seen that r n, compllshed and, preferred 'form of conf:- myself rtire right to providing l do not principle of my I claim es a paf' l. In a sound inten of n membrane, with e center of the membrane, comprising 'a meal cross n to the n'iembralw bending towr hating i i pr membrane, an, from the center the membrane 2. In so vibrating unir. compn s )aced relation to thereto, contact pro-,ng metal cross to the the metal cross tb rom the out saidrvprongs act head of the scr-ew, an tendln from ti cfa membra' J vibrating nnt f the-center of the `I nexnbrane andlparallel the aperture, said aperture bein slightly thereto, prongs at'the ends of the metal larger than the diameter of the ardwood cross in Contact with the membrane, screws pin. 410 to hold the ends of the metal cross t0 the Signd by me at Portland, Oregonyth-is membrane, an aperture in the center of the 11th day OfF6-b1l1ary, 1925- membrune, and u hardwood pin extend' from Ythe gentler of the met-al crosslthroug F. J. -KOEHLER 

